The present invention relates generally to a motor vehicle, and in particular to an engine idle stability control method and system using feedback from an alternator for a motor vehicle.
An engine in a motor vehicle typically must maintain a target idle speed within a specified range. If the engine speed varies outside the specified range, performance and handling characteristics of the motor vehicle, as well as driving comfort, may become poor. In some cases, if engine speed becomes extremely low, the engine may stall.
When an electric load is applied in a vehicle, for example, a load caused by headlights, a radiator fan, power windows, rear window defroster, or other electric load, the motor vehicle's alternator must increase its output to provide more power for the load. When the alternator increases its output, the alternator torque increases, thereby increasing the engine load. When the alternator torque load varies, the engine idle speed can fluctuate out of the specified range for proper engine idle stability.
Accordingly, there is a need in the art for an engine idle stability control system that can help reduce variation in engine idle caused by changes in alternator torque load.